.\" -*- nroff -*-
.TH FROTZ 6 2.44
.SH NAME
frotz \- interpreter for Infocom and other Z-Machine games

.SH SYNOPSIS
.B frotz
.RI [ options "] " file

.SH DESCRIPTION
.B Frotz
is a Z-Machine interpreter.  The Z-machine is a virtual machine designed
by Infocom to run all of their text adventures.  It went through multiple
revisions during the lifetime of the company, and two further revisions
(V7 and V8) were created by Graham Nelson after the company's demise.
The specification is now quite well documented; this version of Frotz
supports version 1.0.
.P
This version of Frotz fully supports all these versions of the Z-Machine
except for version 6.  Version 6 is semi-supported by displaying the
outlines of V6 graphics with the picture number in the bottom-right
corner.


.SH OPTIONS
.TP
.B \-a
Watch attribute setting.  Setting and clearing of attributes on objects
will be noted in debugging messages.

.TP
.B \-A
Watch attribute testing.  Every time the z-machine tests an attribute
value, the test and the result will be reported.

.TP
.B \-b <colorname>
Sets the default background color.  <colorname> corresponds to one of the
Z-machine colors, which are as follows:
.br
.I black red green yellow blue magenta cyan white
.br
If color support is disabled or not available on your terminal, this
option does nothing.

.TP
.B \-c N
Sets the number of context lines used.  By default, after a ``[MORE]''
prompt, and assuming there is enough output pending, Frotz will allow all
the currently visible lines to scroll off the screen before prompting
again.  This switch specifies how many lines of text Frotz will hold
over and display at the top of the next screen.

.TP
.B \-d
Disable color.

.TP
.B \-e
Enable sound.  If you've disabled sound in a config file and want to hear
sound effects, use this.

.TP
.B \-f <colorname>
Sets the default foreground color.  <colorname> corresponds to one of the
Z-machine colors, which are as follows
.br
.I black red green yellow blue magenta cyan white
.br
If color support is disabled or is not available on your terminal, this
option does nothing.

.TP
.B \-F
Force color mode.  If you've disabled color in a config file and want to
Frotz to display colors, use this.

.TP
.B \-h N
Manually sets the screen height.  Though most curses libraries are intelligent
enough to determine the current width from the terminal, it may sometimes
be necessary to use this option to override the default.

.TP
.B \-i
Ignore fatal errors.  If a Z-Machine interpreter encounters a zcode error
such as division-by-zero or addressing an illegal object, the proper
response is to abort execution.  This is done because the zcode program
doesn't have a clear idea of what is going on.  There are some games out
there that cause fatal errors because the authors were careless and used
an interpreter that didn't properly check for errors.  This option is
intended to get around such bugs, but be warned that Strange Things may
happen if fatal errors are not caught.

.TP
.B \-l N
Sets the left margin, for those who might have specific formatting needs.

.TP
.B \-o
Watch object movement.  This option enables debugging messages from the
interpreter which describe the moving of objects in the object tree.

.TP
.B \-O
Watch object location.  These debugging messages detail the locations of
objects in the object tree.

.TP
.B \-p
Plain ASCII output only.  This inhibits the output of accented letters
and other characters from the Latin-1 character set, replacing them with
reasonable alternatives.  This may be necessary on devices lacking these
characters.

.TP
.B \-P
Alter the piracy opcode.  The piracy opcode was never used by Infocom.
This switch is really only useful for those who like to toy around with
Z-code.

.TP
.B \-q
Quiet.  Turns off sound effects.  Useful when running Frotz on a remote
machine and you don't want to bother whoever's near the console with weird
noises.

.TP
.B \-r N
Sets the right margin.

.TP
.B \-s N
Set the random number seed value.  The given seed value is used as the initial
seed value on every restart. This is helpful for testing games like
.B Curses
which make random decisions before the first input (such that the hot
key Alt\-S does not really help).

.TP
.B \-S N
Set the transcript width.  By default your transscript files are formatted
to a width of 80 columns per line, regardless of the current screen width.
This switch allows you to change this setting. In particular, use \-S 0
to deactivate automatic line splitting in transscript files.

.TP
.B \-t
Sets the z-machine's
.I Tandy bit,
which may affect the behavior of certain Infocom games.  For example,
Zork I pretends not to have sequels, and Witness has its language
toned down.

.TP
.B \-u N
Sets the number of slots available for Frotz's multiple undo hotkey (see
below).  This defaults to twenty, which should be sufficient for most
purposes.  Setting too high a number here may be dangerous on machines
with limited memory.

.TP
.B \-w N
Manually sets the screen width.  Again, this should not be necessary
except in special circumstances.

.TP
.B \-x
Expand the abbreviations "g", "x", and "z" to "again", "examine", and
"wait".  This switch is for use with old Infocom games that lack these
common abbreviations which were introduced in later games.  Use it with
caution: A few games might use "g", "x" or "z" for different purposes.

.TP
.B \-Z N
Error checking mode.
.br
0 = don't report errors.
.br
1 = report first instance of an error.
.br
2 = report all errors.
.br
3 = exit after any error.
.br
Default is 1 (report first instance of an error).


.SH CONFIGURATION FILES
On startup,
.B frotz
will first check the system's frotz.conf then $HOME/.frotzrc for
configuration information.  The configuration file uses a simple syntax 
of
.br
<variable> <whitespace> <value>

.PP
Color names may be any of the following:
.br
black\ |\ red\ |\ green\ |\ blue\ |\ magenta\ |\ cyan\ |\ white


.PP
.BR ascii
\ \ on\ |\ off
.br
Use plain ASCII only.  Default is "off".

.PP
.BR background
\ \ <colorname>
.br
Set background color.  Default is terminal's default background color.

.PP
.BR color
\ \ yes\ |\ no
.br
Use color text.  Default is "yes" if supported.

.PP
.BR errormode
\ \ never\ |\ once\ |\ always\ |\ fatal
.br
Set error reporting mode.
.br
.I never
Don't report any errors except for fatal ones.
.br
.I once
Report only the first instance of an error.
.br
.I always
Report every instance of an error.
.br
.I fatal
Abort on any error, even non-fatal ones.
.br
Default is "once".

.PP
.BR expand_abb
\ \ on\ |\ off
.br
Expand abbreviations.  Default is off.  Expand the abbreviations "g", "x",
and "z" to "again", "examine", and "wait".  This switch is for use with
old Infocom games that lack these common abbreviations which were
introduced in later games.  Use it with caution.  A few games might use
the "g", "x", or "z" for different purposes.

.PP
.BR foreground
\ \ <colorname>
.br
Set foreground color.  Default is terminal's default forground color.

.PP
.BR ignore_fatal
\ \ on\ |\ off
.br
Ignore fatal errors.  If a Z-Machine interpreter encounters a zcode error
such as division-by-zero or addressing an illegal object, the proper
response is to abort execution.  This is done because the zcode program
doesn't have a clear idea of what is going on.  There are some games out
there that cause fatal errors because the authors were careless and used
an interpreter that didn't properly check for errors.  This option is
intended to get around such bugs, but be warned that Strange Things may
happen if fatal errors are not caught.
.br
Default is "off"

.PP
.BR piracy
\ \ on\ |\ off
.br
Alter the piracy opcode.  Default is off.  The piracy opcode was never
used by Infocom. This option is only useful for those who like to toy
around with Z-code.

.PP
.BR randseed
\ \ <integer>
.br
Set random number seed.  Default comes from the Unix epoch.

.PP
.BR sound
\ \ on\ |\ off
.br
Turn sound effects on or off.  Default is "on".

.PP
.BR tandy
\ \ on\ |\ off
.br
Set the machine's
.I Tandy bit.
This may affect the behavior of certain Infocom games.  For example, Zork
I pretends not to have sequels, and Witness has its language toned down.
Default is "off".

.PP
.BR undo_slots
\ \ <integer>
.br
Set number of undo slots.  Default is 500.

.PP
.BR zcode_path
\ \ /path/to/zcode/files:/another/path
.br
Set path to search for zcode game files.  This is just like the $PATH
environmental variable except that you can't put environmental variables
in the path or use other shortcuts.  For example, "$HOME/games/zcode" is
illegal because the shell can't interpret that $HOME variable.


.P
The following options are really only useful for weird terminals, weird
curses libraries or if you want to force a certain look (like play in
40-column mode).

.PP
.BR context_lines
\ \ <integer>
.br
Set the number of context lines used.  By default, after a ``[MORE]''
prompt, and assuming there is enough output pending, frotz will allow all
the currently visible lines to scroll off the screen before prompting
again.  This switch specifies how many lines of text frotz will hold over
and display at the top of the next screen.  Default is "0".

.PP
.BR left_margin
\ \ <integer>
.br
Set the left margin.  This is for those who might have special formatting
needs.

.PP
.BR right_margin
\ \ <integer>
.br
Set the right margin.  This is for those who might have special formatting
needs.

.PP
.BR screen_height
\ \ <integer>
.br
Manually set screen height.  Most curses libraries are intelligent enough
to determine the current width of the terminal.  You may need to use this
option to override the default.

.PP
.BR screen_width
\ \ <integer>
.br
Manually set screen width.  Again, this should not be necessary except in
special circumstances.

.PP
.BR script_width
\ \ <integer>
.br
Set the transcript width.  Default is 80 columns per line, regardless of
the current screen width.  This switch allows you to change this setting.
You may set this to "0" to deactivate automatic line-splitting in
transcript files.


.P
The following options are mainly useful for debugging or cheating.

.PP
.BR attrib_set
\ \ on\ |\ off
.br
Watch attribute setting.  Setting and clearing of attributes on objects
will be noted in debugging messages.  Default is "off"

.PP
.BR attrib_test
\ \ on\ |\ off
.br
Watch attribute testing.  Every time the z-machine tests an attribute
value, the test and the result will be reported.  Default is "off".

.PP
.BR obj_loc
\ \ on\ |\ off
.br
Watch object location.  These debugging messages detail the locations of
objects in the object tree.  Default is "off".

.PP
.BR obj_move
\ \ on\ |\ off
.br
Watch object movement.  This option enables debugging messages from the
interpreter which describe the movement of objects in the object tree.
Default is "off".

.SH ENVIRONMENT
If the ZCODE_PATH environmental variable is defined, frotz will search
that path for game files.  If that doesn't exist, INFOCOM_PATH will be
searched.


.SH FURTHER INFORMATION
.PP
A
.BR git(1)
repository of all versions of Unix Frotz back to 2.32 is available 
for public perusal here:
.br
https://github.com/DavidGriffith/frotz/. 
.PP
The bleeding edge of Frotz development may be followed there.  A wiki 
summarising Frotz is also there at this URL:
.br
https://github.com/DavidGriffith/frotz/wiki/
.PP
The Interactive Fiction Archive is a good place to find games to play
with Frotz.  Various ports and builds for Frotz may also be found here.
Here is its URL:
.br
http://www.ifarchive.org/
.PP
Most distributions of Linux and BSD include Frotz in their package 
repositories.

.SH CAVEATS
.PP
The Z Machine itself has trouble with the concept of resizing a terminal.
It assumes that once the screen height and width are set, they will never
change; even across saves.  This made sense when 24x80 terminals were the
norm and graphical user interfaces were mostly unknown.  I'm fairly sure
there's a way around this problem, but for now, don't resize an xterm in
which frotz is running.  Also, you should try to make sure the terminal
on which you restore a saved game has the same dimensions as the one on
which you saved the game.

.PP
You can use a path like "/usr/local/games/zcode:$HOME/zcode" with
$ZCODE_PATH or $INFOCOM_PATH because the shell will digest that $HOME
variable for you before setting $ZCODE_PATH. While processing frotz.conf
and $HOME/.frotzrc, a shell is not used. Therefore you cannot use
environmental variables in the "zcodepath" option within the config files.

.PP
This manpage is not intended to tell users HOW to play interactive
fiction.  Refer to the file HOW_TO_PLAY included in the Unix Frotz
documentation or visit one of the following sites:
.br
http://www.microheaven.com/ifguide/
.br
http://www.brasslantern.org/beginners/
.br
http://www.musicwords.net/if/how_to_play.htm
.br
http://ifarchive.org/

.PP
If you prefer a PDF file of how to play, here is one:
.br
http://inform-fiction.org/I7Downloads/Examples/dm/IntroductionToIF.pdf


.SH BUGS
This program has no bugs.  no bugs.  no bugs.  no *WHAP* thank you.  If 
you find one, please report it to the Github site referenced above in
.B
FURTHER INFORMATION.


.SH AUTHORS
.B Frotz
was written by Stefan Jokisch for MSDOS in 1995-7.
.br
The Unix port was done by Galen Hazelwood.
.br
The Unix port is currently maintained by David Griffith <dave@661.org>.


.SH "SEE ALSO"
.BR dfrotz (6)
.BR nitfol (6)
.BR rezrov (6)
.BR jzip (6)
.BR xzip (6)
.BR inform (1)


